Hard things alone will not make a wall. [Some soft substance must unite them: and so with hard men--to fraternize they require some soft influence from others.]

困难的事情本身并不能构成一堵墙。(某种软性物质必须把他们结合起来,因此要和硬汉交朋友,就需要别人施加一些软性的影响。)